Production of high and low carbon pitches



S. P. MILLER Feba @y 1932 PRODUCTION OF' HLGH AND LOW CARBON PITCHES Filed Dec. 29, 1927 I5 Sheetsheet Feb. 9, 1932. s. P. MILLER' PRODUCTION OF HIGH AND LOW CARBON PITCHES Filed Deo.

29, 1927 3 Sheets-Sheet- 2 Wikis x95 SAQ PQVE\TOR Feb. 9,- 1932. v s. P. MILLER 1,844,898

PRODUCTION OF HIGH AND LOW CARBON PITCHES AT TORNEYS Patented Feb. 9, 1932 g 4Uiu'mn STATES PATENT OFFICE STUART PARMELEE MILLER, OF ENGLEWOOD, NEW JERSEY, ASSIGNOR T THE BARRETT COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY Application led December 29, 1927. Serial No. 243,809.

This invention relates to the simultaneous production of high carbonpitches and of low v carbon pitches of regulated high carbon and low carbon content at coke oven or other coal 5 distillation plants.

In my cpm anion applications, Serial No. 243,305 and scribed the separate recovery of low carbon tar and of high carbon tar respectively from the gases given oi during the early and the later periods of the coke oven or other coal distillation o erations, and the distillation of such low car on tar or of such high carbon tar for the product/ion therefrom ofa low carbon pitch or a high carbon pitch.

The present invention provides an improved method whereby both a high carbon pitch and a'low carbon itch of independently regulated high car on and low carbon 2O content can be simultaneously produced at a coke oven plant.

According to the present invention, I provide for se arately collecting the gases from the indivi ual ovens or retorts during the early portion of the coking or gas making operation,and for separately collecting the gases from the individual ovens or retorts during the later period of the coking or gas' making operation, and for separately collecting the gases from the intermediate period of operation, and in connection with each such separate collecting system, I provide means for separately collecting and keeping separate the low carbon tar, the intermediate carbon tar and the high carbon tar obtained simultaneously from the respective gases and I subject the low carbon tar and the high carloon tar separately to distillation to produce simultaneously a low carbon itch and a high carbon pitch of inde endenti;r regulated low carbon and high car `on content. A pitch of intermediate4 carbon content can also be produced from the tar given oi during the intermediate period of operation.

In my com anion applications, Serial No. 243,306 and erial No. 329,197, I have described the production of composite pitch compositions by distilling lon7 carbon tar or high carbon tar to produce low carbon pitch or high carbon pitch and blending the respecerial No. 243,307, I have de.

tive pitches with tar to give composite products of low' carbon content or high carbon content.

The present invention provides improvements in the simultaneous roduction of such composite high carbon an low carbon pitch compositions whereby the carbon content of the compositions can beindependently and simultaneously regulated at the coke oven or other coal distillation plant.

According to the present invention, instead of providing two collector mains, o ne of which must receive all of the gases which are not directed into the other, I provide three collector mains so that I can collect in one the gases from any desired initial period of the coking or gas making operation, in another the gases from any desired final period of the operation, and a. third in which the gases from the intermediate portion of the operation can be collected. In this Way, the low carbon tar from the initial period of operation can be independently regulated and the high carbon tar from the final period of operation can be independently regulated. Furthermore, when a tar of intermediate composition and przperties is desired, and a pitch of interme iate composition and properties, the gases from only the intermediate period of operation need be separately collected and the tar separated therefrom and subjected to distillation to give a. new pitch composition which is free both from the lower carbon pitch of the initial period of operation and from the higher carbon pitch of the final period of operatlon.

In connection with the three collector mains, I provide three condensing systems for condensing the lighter tars which will be res ectively low carbon, intermediate carbon 9o an high carbon light tars.

There are thus provided, in the practice of the present invention, three separate and disltinct kinds of tar, didering in their carbon properties; and these pitches can be varied independently and can be blended with a wide range of other products to give intermediate and composite pitch compositions covering practically the entire range from the highest carbon pitches to the lowest carhon pitches and including intermediate fractionally separated lars and pitches which, although they may have a carbon content the same as or similar to that of the total tar when collected together, nevertheless diller from total tar of the same carbon content and for some purposes form more valuable products.

In addition. to providing for the independent production and regulation of the pitches,

the present invention provides for the independent regulation of the oils produced by distillation ot' the respective tars. The composition of the tar given oil during the coking period changes from a low carbon tar during the early period of operation to a high carbon tar during the late period of operation. The oils distilled from the low carbon tar are oi" lower specilic gravity and the oils distilled from the high carbon tar are of higher specific gravity. The oils distilled from the low carbon tar are higher in tar acids or phenols, while those distilled iirom the high carbon tar are lower in tar acids or phenols. The oils distilled from the intermediate tars` produced during the intermediate period of operation, are of an intermediate character and distinguished from hoth the higher gravity oils produced from the high carbon tars and the lower gravity oils produced from the low carbon tars.

The separate distillation of the high, low and intermediate carbon tars can be carried out in ordinary7 tar stills, out is advantageously carried out at the colle oven or gas retort plant by bringing the respective tars into direct and intimate contact with the hot coke oven or other coal distillation gases at a sutilcient temperature to ellect rapid distillation. The gases employed for the distillation are advantageously those corresponding to the gases from which the respective tars are separated, so that, for example, the high carbon tar is distilled by gases from which high carbon pitch will he separated, and the low carbon tar is distilled by gases from which low carbon pitch will he. separated. By operat ing in this Way, the pitch produced hy the distillation and the pitch separated from the gases employed for the distillation will be pitch of the same or similar carhon content and pitches of regulated high or low or interu mediate carbon content can be produced.

In some cases, however, such close regula.- tion of the carbon content is not required and the total gases from a selected number of ovens can be employed for the distillation of the respectivetars. In such case, the pitch separated Vfrom the gases will have an aver age carhon content and will or may modify the carbon' content of the pitch produced. For example, if high carbon tar is distilled in the total gases from a selected number of ovens the pitch produced will be a composite product made up of the high carhon pitch` resulting from the distillation of the tar and the lower carbon composite pitch separated from the gases, giving a composite total pitch product of lower carbon content than would be produced if the high carbon tar were disu tilled in gases from which high carbon pitch could be separated. Similarly, if low carbon tar is distilled in the total gases from a selected number of ovens the carbon content of the resulting pitch will he somewhat higher than it would he if the low carbon tar were distilled in rich gases from which low carbon pitch of' similar carbon content could be separated during the distillation. The selection of the carbon content of the tar distilled and of the gases employed for the distillation enahles a wide range 'of pitch products olf regulated high or low carbon 'content to he pro duced.

For the distillation o'l all three tars, I provide three separate stills or distilling mains or boxes into which the tar is introduced and in which it is intimately brought into contact with the hot coke even or other coal distillation. gases, and into which the gases from a selected number of ovens or retorts are introdueed for eilecting the distillation It is sometimes advantageous to distill separately the heavy tar from the collector main and the lighter tar from the condensers, since the heavier tars give a pitch with less distilla` tion, and the lighter tars give increased oil yields for the tar distilled. A greater or a smaller number of stills may be provided dcpending upon the particular operation.

Where it is desired to distill simultaneously both the heavy tar and the lighter tar, more than three distillation stills may be provided; or the products can he collected and stored and subjected to distillation at different times in the same stills.

The operation of the three collector mains may he much the same as in systems where only a single main is provided. That is, the gases in the individual collector mains may be cooled by the introduction of' ammonia liquor, or the circulation ol ammonia liquor and tar therethrough, so that there will he thrown down a greater part of the tar as a heavy tar whichis drawn oil separately from each of the collector mains and kept separate for subsequent separate distillation. The lighter tars or tarry oils from the condensers are also kept separate from each other, and

a plurality of products may be obtained from the diierent stages of the same condenscrs. which separate products may also be kept separate and separately distilled.

In order that the distillation of the respec llG tive tars may be carried out to give not only pitches of regulated carbon content and other properties, but also a `high yield of the individual oils, and in order that the oils may be obtained in a relatively clean state, that is, relatively free from heavy ,tar and pitch constituents, the gases employed for the distillation are advantageously cleaned to remove therefrom all or the greater part of the tar fog or suspended tar and pitch particles. This can readily be effected for example, by passing the gases, subsequent to their employment for distillation, through an electrical precipitator at a high temperature, or through a pitch scrubber at a high temperature. It can also be advantageously effected by subjecting the gases employed for the distillationto such intimate contact With the tar or pitch being distilled as to effectively scrub the gases and free them from all or the greater part of the suspended tar and pitch constituents, leaving only or mainly volatile oils in vapor form inthe gases leaving thel still. Such cleaned gases and vapors, after separation of entrained heavy particles of pitch by settling or by amechanical separator, will, on cooling, give clean or relatively clean oils Which will differ from each other with the particular tar being distilled, and

which can be fractionally condensed to give afvvide variety of different oil distillates, dit :tering from each other in specific gravity, viscosity and composition.

The invention will be further described in connection With the accompanying drawings, Which illustrate, in a somewhat conventional and diagrammatic manner, one form of apparatus embodying the invention and adapted for the carrying out of the process of the invention.

In the accompanying drawings Fig. 1 is a plan View showing part of a coke oven plant, with parts broken away;

Fig. 2`is a partial elevation of the plant of Fig. 1;

Figs. 3 and 4 are sectional views showing modified forms of stills; v Fig. 5 shows a baille tower used on one o the stills, and Y Fig. 6 shovvs an electrical precipitator arranged for use on one of the stills.

In the drawings, the coke ovens 1 have the usual uptake pipes 2 but these uptake pipes are connected with three separate collector mains 3, 4 a'nd 5 and have valves 6, 7 and 8 for connecting each uptake pipe with any one of the three mains.

Three cross-over mains 9, 1,0 and 11 lead from the three collector mains to condensing systems, only one 'of which, that connected to the cross-over main 11, is shown. The crossover main llleads to a common main 12, connected to tvvo or more cross-over mains at different parts of the battery. The mai-n 12 leads to condensers 13 and 14 which may be of the indirect or direct type but which are shown as of the direct type with provision for the introduction of l cooling liquids through spray pipesl at the top of the condensers. From the condensers, the gases escape through line 16 to exhauster 17 and to the ammonia absorber, and if desired to the benzol scrubber (not shown). The three collector mains are shown as cooled by the introduction of ammonia liquor supplied through the pipe 20 and sprayed into the uptake pipes through spray nozzles 18 and'into the collector mains through spray nozzles 19.

Each of the collector mains is provided with a separate tar draw-od for drawing off therefrom and keeping separate the tar which collects therein. Only one such tar collecting system for one of the mains is shown in Fig. 1, the others being omitted for simplicity of illustration. The tar .from the collector main 4 flows out therefrom through the center box and the pipe 23 to the separating tank or.`

decanter 24 for separating the ammonia liquor from the tar, andthe tar then ilows to the tank 26 and the ammonia liquor to the tank 25. 4

From the tar tank 26 the tar is pumped through line 28 by pump 29 to pipe 3G, leading to still 32 shown as arranged on the opposite side of the coke oven block from that at which the collector mains are located. The still 32 is one of three stills 31, 32 and 33, provided for distilling the tar from each of the collector mains 3, 4 and 5, or the tar from the condensers connected to these respective collector mains.

At the end of the cross-over mains 11 and 12is provided another tar separator or dec'anter 35 for separat-ing ammonia liquor' from tar, the ammonia liquor being drawn ott through pipe 36 and the tar to tank 37 from which it may be, it desired, pumped by pump 38 through-line 39 to line 30 and to the still 32 for distillation.

The condensers 13 and 14 are shown as having a single tar separator or decanter 40, for collecting all of the tar from both condensers together, although the tars from the separate condensers may, if desired, be kept separate. The ammonia liquor separating in the separator 40 is collected in tank 41 While the tar is collected in tank 42 and may, if desired, be pumped back by pump 43 through the line 44 to the line 30 and to the still 32.

Ammonia liquor from the tank 25 may be .pumped by pump 45 through line 46 Vand line 2O to the collector mains. Ammonia liquor from the tank 41 maybe Worked up for recovery of ammonia.

Each of the stills is connected to a plurality of uptake pipes leading from different ovens so that the gases from a. larger or smaller number of ovens can be passed into each of the stills. These uptakes are indicated at 48, but We are not limited to 'the number shown. The tar enters the still at one end through tar inlet 49 and the pitch leaves the still at the other end through pitch outlet 52 and passes to pitch storage tank 53 or to other place of disposal or use.

Each still is provided with means for atomizing or spraying the tar and pitch to insure intimate Contact thereof with the hot gases coming from the ovens into the still. In Fig. 3 discs 5l are shown mounted on a shaft 68 which is provided with an electric motor 67. The level' of liquid is maintained preferably so that the discs 51 dip slightly belovvr thelevel when the still is in operation. By means of the electric motor, the shaft 68 and discs are rotated at a high rate of speed so that thetar isthrown into the space above the discs in a finely divided state and in great quantity. YThe particles of tar are so intimately mixed With the gases entering the still from nptakes 48 that the tar 'fog and other entrained matter is removed from the gases substantially completely, this being accomplished partly in the distilling main and partly as the gases pass up through the settling spaces above the still. In Fig. 4 a rota-ting roll 51a is used instead of the discs to atomize or spray the tar into the gases. F ig. 5 shows a preferred arrangement of ,a-settling tower above the still. In Fig. 5 the tower 63 is shown as equipped with baiiies 6ft to aid in the removal of the tar fog. Tar may be introduced through tar line to preheat the tar as it passes down over baille 64. In Fig. 6 is shown an electrical precipitator 66, for the purpose of removing any entrained matter from the gases, .which will be returned to the still.

The gas and oil vapor resulting 'trom the distillation leaves the still through gas outu let pipe 55 and passes through a main or pipe 5G to condensers 57 and 58.- I :tracvtional condensation of the oils is desired, plurality of condensers Will be employed and the condensates will be kept separate. .In the apparatus illustrated., the tivo condensers 57 and 58 discharge the condensed oils into a ccinn'ion tank 59. The condensers shown as of the direct type cooled by the introduction of a cooling liquid, such as Water or ammonia liquor, which can be separated Afrom the oils in'the separating tank 59 and the oils collected in tank 6l and the ammonia liquor in tank 60. The gases leaving the condensers pass to the exhauster '17 along with the gases from the condensers 13 and 14.

`While only one still and one systeinconnccted therewith has been illustrated in detail and described, it will oe understood that each of the stills will have similar connections and condensers so as to provide three complete and independent systems Afor collecting tar from the gases in three collector mains and three condensing systems and for returniiw the tar from either the collector mains or from the conce-risers, or any desired oart of the tar from each system to a still J" s l -l ,.1 1

tnereior, 4in Whicn the tar is distilled and pitch produced and distillate oils recovered.

from the gases.

In the operation of the apparatus and the carrying ont of the process, the gases 'from any desired initial period of operation of the coke ovens Will be collected in one of the mains, for example, the main 3, and cooled' therein 'to give a low carbon tar, and the gases leaving the collector main Will be further cooled in the cross-over main and in the condensers to give lighter tars or tarry oil Which will likewise be characterized by a lov7 carbon content.

The gases from any desired final portion of the coking operation can be collected to gether in one of the collector mains, for eX- ample, the main 5, and cooled therein to separate a high carbon tar, While lighter tars of high carbon content will be recovered from the condensers connected to this collector main.

So also, the gases from the intermeiate portion of the coking operation vvhich remain after the desired initial portion oit the gases and the desired final portion of the gases have been separately collected, pass to the third collector main 4l Awhere they are cooled and tar separated therefrom, and the gases further cooled in the condensers for the separation oi lighter tar. This tar from the intermediate period of operation will be of intermediate carbon content. t' it is desired to produce an intermediate tar of regulated carbon content, this can readily be accomn plished by regulating the intermediate period' of operation of Vthe ovens, tromY which the gases are collected in the intermediate collector inain, and allowing the remaining portion oit' the gases given oil during' the initial and the final periods-ot' operation to he collected in the other tivo mains or even in one of the mains.

The high, intermediate and low carbon tars collected from the collector mains, or from the end of the crossover mains, or from. part or all of the concensers, are kept separate and part or all of these tars can he subjected to distillation in the respectivo rar stills to produce therefrom high, intermediate or low carbon pitches and distillate oils corresponding to the tars distilled. 'Either the heavy tar from' the collector Amain can be distilled hy itself, or the lighter tar from the condensers, or the total tar 'from the collector main and condensers may be distilled together, for example, the total low carbon tar can be distilled to give a low carbon pitch, and distillate oils of relatively lov.7 specific gravity. The high carbon tar can similarly be distilled to give high carbon pitch and distillate oils of relatively high specific gravity;

While the intermediate tar Will give intermediate pitch and oils.

three collector mains permits the carbon content and other properties of the loW carbon pitch and of the high carbon pitch to be 'simultaneously and independently regulated, or enables an intermediate pitch of regulated properties to be produced.

I/Vhen the gasesare effectively scrubbed and cleaned by the spray in the still, and the entrained particles are separated, for example, by a baiiie tower or electrical precipitator, the oils condensed from the gases Will be 'clean oils free or substantially free from heavy tar and pitch constituents. These oils,

by fractional condensation, Will give heavier and lighter oil fractions diiering fromeach other, depending upon the. kind of tar from which they are distilled.

The present invention isgof particular ad vantage in connection with coke oven`plant operations. It is also applicable, in its broadei aspects, to other coal distillation plants where the gases can similarly be separated to give low carbon tars and high carbon tars during the early and later periods of operation, together With an intermediate tar from the gases given otl during the intermediate period of operation.

The present invention also enables a Wide range of blended pitch products to be produced such as described, for example, in my companion applications Serial No. 243,808 and Serial No. 243,306. In addition, the

be produced from the pitch of intermediate carbon content obtained by separate distillation of theA tar of intermediate carbon content separated from the coke oven orother coal distillation gases during an intermediate period of operation. With high, low and intermediate carbon pitches available, and with high, low and intermediate carbon tars available, both heavier tars troni the collector mains and lighter tars from the condensers, there are available at the coke oven or other coal distillation plants, a Wide range of pitches and tars Which can be blended in a Wide range of proportions to form blended pitch compositions having a Wide range of carbon content. The new intermediate carbon content pitch can, for example, be blended with tar of intermediate carbon content or With tar of high or low carbon content tov give new composite pitch compositions.

The carbon content of the pitch produced can be regulated not only b v regulating the carbon content' of the tar distilled but also in part by employing gases from an early, intermediate or late portion of the coking operationfrom which low, intermediate or high carbon pitches ivill be separated and become blended with the pitch residue from the distillation. For example, the still employed for the distillation ot' high carbon tar may be The provision of present invention enables blended pitches to connected only with ovens which are at an advanced stage of the coking period so that high carbon pitch Will be Separated from them during the distillation. A high carbon pitch of regulated high carbon content can thus be obtained. Similarly the distillation main or still in Which low carbon tar is distilled may be connected only to ovens which are at an initial stage of the coking period so that low carbon pitch will be separated from the gasesduring the distillation. In other cases the total gases from a selected number of ovens can be employed for distilling either the high or the lovv carbon tar in which case the high carbon pitch and the low carbon pitch produced Will have their respective carbon contents lowered or increased by the pitch separated from the total gases einployed for the distillation. In this Way pitchesof varying and regulated carbon content can be produced and a Wide range of different pitch products can be simultaneously produced.

I claim A l. The method of producing high free carbon pitch and low free carbon pitch of independently regulated free carbon content from coke oven or other coal distillation gases, which comprises collecting separately the gases given ott during a regulated early portion of the coal distillation in such oven or retorts, collectingseparately the gases given rofl during a regulated later period of distillation in such ovens or retorts, Which earlier and later periods are independently regulated and together are less than the total period of distillation in the ovens or retorts, keeping separate the respective gases collected during the early period of distillation and those collected during the later period of distillation, cooling the respective gases to separate tars of different free carbon content, and separately distilling the respective tars to produce pitches of dierent. free car'- bon content.

2. The method of producing coal tar pitch of intermediate free carbon content Jfrom ,coke oven andother coal distillation gases,

which 'comprises collecting separately the gases given off during an intermediate period of the coal distillation in such ovens or retorts, which intermediate gases do not include the gases produced during the early period of distillation, and also do not include the `ases produced during the later period of distillation, in such ovens or retorts, cooling such intermediate gases While maintained,

separate from the other gases to separate tar therefrom, and subJecting such'tar by itself :to distillation to produce pitch therefrom.

3. The method of producing lower, intermediate and higher free carbon pitches which comprises collecting separately the gases given ofip during the early, intermediate and later vperiods of the coal distillation in coal distillation ovens or retorts, se arately cooling the respective gases to separate therefrom tars o1 lower, intermediate and higher free carbon content, and subjecting such tars separately to distillation for the production therefrom of pitches of lower, intermediate and higher 4l'ree earhon content 4. The method of producing` high freecarbon and low free carbon pitches of independently related 'free carbon content, Which cornprises collecting separateljy the gases given olf during a regulated early period and during an independently regulated later period of the distillation of coal in ovens or retorts, cooling such respective gases to separate tars of low and high free carhon content there- Ifrom, and subjecting the tars so prcluced separately lto distillation hy hringing them into direct and intimate Contact with hot coalI distillation gases to produce pitches therefrom.

5. The method of producing pitches of lower and higher free carbon content at coal distillation plants, which comprises collecting separately the gases given o' during an early period, an intermediate period, and a later period of the distillation of the coal in the ovens or retorts of the plant, cooling the respective gases to separate therefrom tars c of lower, intermediate and higher tree carbon content, and separately subjecting the tars of lower and higher free carhon content to distillation by hringing them into direct contact with hot coal distillation lgases to produce higher and lower -'ree carhonpitches therefrom.

6. The method of producing coal tar pitch of intermediate free carhon content, which comprises collecting separately the gases given ofi during an intermediate period of the distillation of coal in the ovens or retorts of a coal distillation plant, which gases are 'free or suhstantiallyfree from gases given off during the initial and final period of coal distillation in these ovens or retorts, cooling the gases given olf during such intermediate period to separate tar of intermediate free carbon content, and subjecting such tar to distillation hy bringing it into intimate con- 'tact with hot coal distillation gases to distill the tar and produce pitch of intermediate free carbon content therefrom.

In testiinonv whereof l aix mv signature.

STUART Plinn-nnen inLLEn.

nseeeee 

